The present invention relates to an apparatus for subjecting a target object to a plasma process in a semiconductor processing system by using a plasma and, more particularly, to an inductively coupled type dry etching apparatus. The term "semiconductor processing" used herein includes various kinds of processes which are performed to manufacture a semiconductor device or a structure having wiring layers, electrodes, and the like to be connected to a semiconductor device, on a target substrate, such as a semiconductor wafer or an LCD substrate, by forming semiconductor layers, insulating layers, and conductive layers in predetermined patterns on the target substrate.
As a plasma processing apparatus used in semiconductor processing systems, there is an inductively coupled type dry etching apparatus. This dry etching apparatus generally has a process chamber with a ceiling of a dielectric wall, on which an annular or spiral RF (radio-frequency) antenna is disposed.
During a plasma process, the RF antenna and a plasma excited in the process chamber are coupled not only inductively but also capacitively. Consequently, the inner surface of the dielectric wall made of, e.g., quartz, which is exposed to the interior atmosphere of the process chamber near the RF antenna, is charged with a negative bias relative to the plasma. With the potential difference between the plasma and the exposed inner surface of the dielectric wall, positive ions in the plasma collide with the exposed inner surface while being accelerated. As a result, problems arise in that contaminants are produced in the process chamber and the dielectric wall is worn off quickly.
In order to cope with these problems, Jpn. Pat. Appln. KOKAI Publication No. 8-153702, corresponding to U.S. Pat. application Ser. No. 08/005,678 now U.S. Pat. No. 5,433,812 filed on Jan. 19, 1993, discloses a conductive Faraday shield to be arranged between a dielectric window and an insulating layer under an RF antenna. The capacitive coupling between the RF antenna and the plasma is broken off by the Faraday shield, so that the exposed inner surface of the dielectric wall is prevented from being collided into by accelerated positive ions from the plasma. However, where the Faraday shield is used, thermal stress is caused among the dielectric window, insulating layer, and the RF antenna due to an inductive heating, thereby generating cracks therein.